背景:非药物干预(NPI)和环疫苗接种(即主要针对埃博拉病例接触者和接触者的疫苗接种)目前用于减少埃博拉疫情期间的传播。因为这些措施通常是在宣布爆发后启动的,它们受到实时实施挑战的限制。预防性疫苗接种可以提供一种补充选择,以帮助保护社区免受不可预测的暴发。本研究旨在评估与NPI和环疫苗接种一起实施的预防性疫苗接种策略的影响。
方法:空间显式,基于个人的模型(IBM),它解释了人类接触的异质性,人类运动,干预措施的时间安排是为了代表埃博拉病毒在刚果民主共和国的传播。针对医护人员(HCW)的模拟预防性疫苗接种策略,前线工人(FW),和覆盖率不同的普通人群(GP)(覆盖率较低:HCW/FW的30%,5%的GP;更高的覆盖率:60%的HCW/FW,GP的10%)和疗效(较低的疗效:60%;较高的疗效:90%)。
结果:IBM估计,为HCW增加预防性疫苗接种减少了病例,住院治疗,与仅NPI+环疫苗接种相比,死亡率下降11%至25%。在预防性疫苗接种运动中包括HCW和FW,在流行病结果方面有14%至38%的改善。进一步包括GP产生了最大的改进,与仅NPI+环疫苗接种相比,流行病结局降低了21%至52%。在没有接种戒指的情况下,预防性疫苗接种减少了病例,住院治疗,与仅NPI相比,死亡率下降了28%至59%。在所有情况下,预防性疫苗接种减少了埃博拉的传播,特别是在流行病的初始阶段,导致更平坦的流行曲线。
结论:IBM表明预防性疫苗接种可以减少埃博拉病例,住院治疗,和死亡,从而保护医疗保健系统,并在爆发期间提供更多时间来实施额外的干预措施。
Nonpharmaceutical interventions (NPI) and ring vaccination (i.e., vaccination that primarily targets contacts and contacts of contacts of Ebola cases) are currently used to reduce the spread of Ebola during outbreaks. Because these measures are typically initiated after an outbreak is declared, they are limited by real-time implementation challenges. Preventive vaccination may provide a complementary option to help protect communities against unpredictable outbreaks. This study aimed to assess the impact of preventive vaccination strategies when implemented in conjunction with NPI and ring vaccination.
A spatial-explicit, individual-based model (IBM) that accounts for heterogeneity of human contact, human movement, and timing of interventions was built to represent Ebola transmission in the Democratic Republic of the Congo. Simulated preventive vaccination strategies targeted healthcare workers (HCW), frontline workers (FW), and the general population (GP) with varying levels of coverage (lower coverage: 30% of HCW/FW, 5% of GP; higher coverage: 60% of HCW/FW, 10% of GP) and efficacy (lower efficacy: 60%; higher efficacy: 90%).
The IBM estimated that the addition of preventive vaccination for HCW reduced cases, hospitalizations, and deaths by ∼11 % to ∼25 % compared with NPI + ring vaccination alone. Including HCW and FW in the preventive vaccination campaign yielded ∼14 % to ∼38 % improvements in epidemic outcomes. Further including the GP yielded the greatest improvements, with ∼21 % to ∼52 % reductions in epidemic outcomes compared with NPI + ring vaccination alone. In a scenario without ring vaccination, preventive vaccination reduced cases, hospitalizations, and deaths by ∼28 % to ∼59 % compared with NPI alone. In all scenarios, preventive vaccination reduced Ebola transmission particularly during the initial phases of the epidemic, resulting in flatter epidemic curves.
The IBM showed that preventive vaccination may reduce Ebola cases, hospitalizations, and deaths, thus safeguarding the healthcare system and providing more time to implement additional interventions during an outbreak.